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volunteer.html      3) 

en/volunteer.wml    4) #include "head.wmi" TITLE="Tor: Volunteer"

volunteer.html      5) 
volunteer.html      6) <div class="main-column">
volunteer.html      7) 
volunteer.html      8) <!-- PUT CONTENT AFTER THIS TAG -->

en/volunteer.wml    9) <h2>A few things everyone can do now:</h2>

volunteer.html     10) <ol>

en/volunteer.wml   11) <li>Please consider <a href="<page docs/tor-doc-relay>">running
en/volunteer.wml   12) a relay</a> to help the Tor network grow.</li>
en/volunteer.wml   13) <li>Tell your friends! Get them to run relays. Get them to run hidden

volunteer.html     14) services. Get them to tell their friends.</li>

en/volunteer.wml   15) <li>If you like Tor's goals, please <a href="<page donate>">take a moment
en/volunteer.wml   16) to donate to support further Tor development</a>. We're also looking
en/volunteer.wml   17) for more sponsors &mdash; if you know any companies, NGOs, agencies,
en/volunteer.wml   18) or other organizations that want anonymity / privacy / communications
en/volunteer.wml   19) security, let them know about us.</li>
en/volunteer.wml   20) <li>We're looking for more <a href="<page torusers>">good examples of Tor
en/volunteer.wml   21) users and Tor use cases</a>. If you use Tor for a scenario or purpose not
en/volunteer.wml   22) yet described on that page, and you're comfortable sharing it with us,
en/volunteer.wml   23) we'd love to hear from you.</li>

volunteer.html     24) </ol>
volunteer.html     25) 

en/volunteer.wml   26) <a id="Usability"></a>

en/volunteer.wml   27) <h2><a class="anchor" href="#Usability">Supporting Applications</a></h2>

volunteer.html     28) <ol>

en/volunteer.wml   29) <li>We need more good ways to intercept DNS requests so they don't "leak" their

en/volunteer.wml   30) request to a local observer while we're trying to be anonymous. (This
en/volunteer.wml   31) happens because the application does the DNS resolve before going to
en/volunteer.wml   32) the SOCKS proxy.)</li>

en/volunteer.wml   33) <li>Tsocks/dsocks items:

en/volunteer.wml   34) <ul>
en/volunteer.wml   35) <li>We need to <a

en/volunteer.wml   36) href="https://wiki.torproject.org/noreply/TheOnionRouter/TSocksPatches">apply

en/volunteer.wml   37) all our tsocks patches</a> and maintain a new fork. We'll host it if
en/volunteer.wml   38) you want.</li>
en/volunteer.wml   39) <li>We should patch Dug Song's "dsocks" program to use Tor's
en/volunteer.wml   40) <i>mapaddress</i> commands from the controller interface, so we
en/volunteer.wml   41) don't waste a whole round-trip inside Tor doing the resolve before
en/volunteer.wml   42) connecting.</li>
en/volunteer.wml   43) <li>We need to make our <i>torify</i> script detect which of tsocks or
en/volunteer.wml   44) dsocks is installed, and call them appropriately. This probably means
en/volunteer.wml   45) unifying their interfaces, and might involve sharing code between them
en/volunteer.wml   46) or discarding one entirely.</li>
en/volunteer.wml   47) </ul>

en/volunteer.wml   48) </li>

en/volunteer.wml   49) <li>People running relays tell us they want to have one BandwidthRate

en/volunteer.wml   50) during some part of the day, and a different BandwidthRate at other
en/volunteer.wml   51) parts of the day. Rather than coding this inside Tor, we should have a
en/volunteer.wml   52) little script that speaks via the <a href="<page gui/index>">Tor
en/volunteer.wml   53) Controller Interface</a>, and does a setconf to change the bandwidth

en/volunteer.wml   54) rate. There is one for Unix and Mac already (it uses bash and cron),

en/volunteer.wml   55) but Windows users still need a solution.

en/volunteer.wml   56) </li>

en/volunteer.wml   57) <li>Tor can <a

en/volunteer.wml   58) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#ChooseEntryExit">exit

en/volunteer.wml   59) the Tor network from a particular exit node</a>, but we should be able
en/volunteer.wml   60) to specify just a country and have something automatically pick. The
en/volunteer.wml   61) best bet is to fetch Blossom's directory also, and run a local Blossom
en/volunteer.wml   62) client that fetches this directory securely (via Tor and checking its
en/volunteer.wml   63) signature), intercepts <tt>.country.blossom</tt> hostnames, and does
en/volunteer.wml   64) the right thing.</li>

volunteer.html     65) <li>Speaking of geolocation data, somebody should draw a map of the Earth

en/volunteer.wml   66) with a pin-point for each Tor relay. Bonus points if it updates as the

en/volunteer.wml   67) network grows and changes. Unfortunately, the easy ways to do this involve
en/volunteer.wml   68) sending all the data to Google and having them draw the map for you. How
en/volunteer.wml   69) much does this impact privacy, and do we have any other good options?</li>

volunteer.html     70) </ol>
volunteer.html     71) 

en/volunteer.wml   72) <a id="Documentation"></a>
en/volunteer.wml   73) <h2><a class="anchor" href="#Documentation">Documentation</a></h2>

volunteer.html     74) <ol>

en/volunteer.wml   75) <li>Please help Matt Edman with the documentation and how-tos for his

en/volunteer.wml   76) Tor controller,
en/volunteer.wml   77) <a href="http://vidalia-project.net/">Vidalia</a>.</li>

en/volunteer.wml   78) <li>Evaluate and document

en/volunteer.wml   79) <a href="https://wiki.torproject.org/wiki/TheOnionRouter/TorifyHOWTO">our

en/volunteer.wml   80) list of programs</a> that can be configured to use Tor.</li>

volunteer.html     81) <li>We need better documentation for dynamically intercepting

en/volunteer.wml   82) connections and sending them through Tor. tsocks (Linux), dsocks (BSD),

en/volunteer.wml   83) and freecap (Windows) seem to be good candidates, as would better
en/volunteer.wml   84) use of our new TransPort feature.</li>

en/volunteer.wml   85) <li>We have a huge list of <a href="https://wiki.torproject.org/noreply/TheOnionRouter/SupportPrograms">potentially useful

volunteer.html     86) programs that interface to Tor</a>. Which ones are useful in which
volunteer.html     87) situations? Please help us test them out and document your results.</li>

en/volunteer.wml   88) <li>Help translate the web page and documentation into other
en/volunteer.wml   89) languages. See the <a href="<page translation>">translation

en/volunteer.wml   90) guidelines</a> if you want to help out. We especially need Arabic or
en/volunteer.wml   91) Farsi translations, for the many Tor users in censored areas.</li>

volunteer.html     92) </ol>
volunteer.html     93) 

en/volunteer.wml   94) <a id="Coding"></a>

en/volunteer.wml   95) <a id="Summer"></a>
en/volunteer.wml   96) <a id="Projects"></a>

en/volunteer.wml   97) <h2><a class="anchor" href="#Projects">Good Coding Projects</a></h2>

en/volunteer.wml   98) 
en/volunteer.wml   99) <p>
en/volunteer.wml  100) You may find some of these projects to be good <a href="<page
en/volunteer.wml  101) gsoc>">Google Summer of Code 2008</a> ideas. We have labelled each idea

en/volunteer.wml  102) with how useful it would be to the overall Tor project

en/volunteer.wml  103) (priority), how much work we expect it would be (effort level), how much
en/volunteer.wml  104) clue you should start with (skill level), and which of our <a href="<page

en/volunteer.wml  105) people>#Core">core developers</a> would be good mentors. There are plenty
en/volunteer.wml  106) of other good ideas to work on too &mdash; see for example the <a
en/volunteer.wml  107) href="<svnsandbox>doc/spec/proposals/">current proposals</a> list, or
en/volunteer.wml  108) just make up your own ideas.

en/volunteer.wml  109) </p>
en/volunteer.wml  110) 

en/volunteer.wml  111) <ol>
en/volunteer.wml  112) 

en/volunteer.wml  113) <li>

en/volunteer.wml  114) <b>Tor Exit Scanner improvements</b>

en/volunteer.wml  115) <br />

en/volunteer.wml  116) Priority: <i>High</i>
en/volunteer.wml  117) <br />
en/volunteer.wml  118) Effort Level: <i>High</i>
en/volunteer.wml  119) <br />

en/volunteer.wml  120) Skill Level: <i>High</i>
en/volunteer.wml  121) <br />

en/volunteer.wml  122) Likely Mentors: <i>Mike</i>

en/volunteer.wml  123) <br />

en/volunteer.wml  124) Applications as of 1 Apr 00:00 UTC: <i>5</i>

en/volunteer.wml  125) <br />

en/volunteer.wml  126) The Tor exit node scanner 'SoaT', part of the <a
en/volunteer.wml  127) href="<svnsandbox>torflow/">Torflow project</a>, makes connections out
en/volunteer.wml  128) of each Tor exit node and compares the content it gets back with what it
en/volunteer.wml  129) "should" get back. The goal is to notice misconfigured, broken, and even
en/volunteer.wml  130) malicious exit relays. Alas, the code is
en/volunteer.wml  131) currently written in rather rickety perl and relies on MD5sums of
en/volunteer.wml  132) entire documents in order to determine if exit nodes are modifying
en/volunteer.wml  133) content. The problem with this is threefold: 1) Perl sucks at life.
en/volunteer.wml  134) 2) The scanner can't verify pages that are dynamic, and attackers can
en/volunteer.wml  135) focus malicious content injection on only those dynamic pages. 3)
en/volunteer.wml  136) Pages change after a while (or based on GeoIP) and begin generating
en/volunteer.wml  137) false positives.

en/volunteer.wml  138) <br />

en/volunteer.wml  139) Ideally, soat.pl would be reimplemented in a sane language with a
en/volunteer.wml  140) robust html parser library (since the rest of Torflow is in Python
en/volunteer.wml  141) that would be nice, but it is not required), and calculate signatures only for
en/volunteer.wml  142) tags and content likely to be targeted by a malicious attacker (script
en/volunteer.wml  143) tags, object links, images, css). It should also be robust in the face of
en/volunteer.wml  144) changes to content outside of Tor, and ultimately even GeoIP localized
en/volunteer.wml  145) content.
en/volunteer.wml  146) <br />
en/volunteer.wml  147) This scanner would likely be run by the Directory Authorities and
en/volunteer.wml  148) report its results to the control port via the AuthDirBadExit config
en/volunteer.wml  149) setting.

en/volunteer.wml  150) <br />
en/volunteer.wml  151) </li>
en/volunteer.wml  152) 
en/volunteer.wml  153) <li>

en/volunteer.wml  154) <b>Tor Node Scanner improvements</b>

en/volunteer.wml  155) <br />

en/volunteer.wml  156) Priority: <i>High</i>

en/volunteer.wml  157) <br />

en/volunteer.wml  158) Effort Level: <i>Medium to High</i>

en/volunteer.wml  159) <br />
en/volunteer.wml  160) Skill Level: <i>Medium to High</i>
en/volunteer.wml  161) <br />

en/volunteer.wml  162) Likely Mentors: <i>Mike</i>

en/volunteer.wml  163) <br />

en/volunteer.wml  164) Applications as of 1 Apr 00:00 UTC: <i>1</i>

en/volunteer.wml  165) <br />

en/volunteer.wml  166) Similar to the exit scanner (or perhaps even during exit scanning),
en/volunteer.wml  167) statistics can be gathered about the reliability of nodes. Nodes that
en/volunteer.wml  168) fail too high a percentage of their circuits should not be given
en/volunteer.wml  169) Guard status. Perhaps they should have their reported bandwidth
en/volunteer.wml  170) penalized by some ratio as well, or just get marked as Invalid. In
en/volunteer.wml  171) addition, nodes that exhibit a very low average stream capacity but
en/volunteer.wml  172) advertise a very high node bandwidth can also be marked as Invalid.
en/volunteer.wml  173) Much of this statistics gathering is already done, it just needs to be
en/volunteer.wml  174) transformed into something that can be reported to the Directory
en/volunteer.wml  175) Authorities to blacklist/penalize nodes in such a way that clients
en/volunteer.wml  176) will listen.

en/volunteer.wml  177) <br />

en/volunteer.wml  178) In addition, these same statistics can be gathered about the traffic
en/volunteer.wml  179) through a node. Events can be added to the <a
en/volunteer.wml  180) href="https://www.torproject.org/svn/torctl/doc/howto.txt">Tor Control
en/volunteer.wml  181) Protocol</a> to
en/volunteer.wml  182) report if a circuit extend attempt through the node succeeds or fails, and
en/volunteer.wml  183) passive statistics can be gathered on both bandwidth and reliability
en/volunteer.wml  184) of other nodes via a node-based monitor using these events. Such a
en/volunteer.wml  185) scanner would also report information on oddly-behaving nodes to
en/volunteer.wml  186) the Directory Authorities, but a communication channel for this
en/volunteer.wml  187) currently does not exist and would need to be developed as well.
en/volunteer.wml  188) </li>
en/volunteer.wml  189) 
en/volunteer.wml  190) <li>
en/volunteer.wml  191) <b>Help track the overall Tor Network status</b>

en/volunteer.wml  192) <br />

en/volunteer.wml  193) Priority: <i>High</i>
en/volunteer.wml  194) <br />
en/volunteer.wml  195) Effort Level: <i>Medium</i>
en/volunteer.wml  196) <br />
en/volunteer.wml  197) Skill Level: <i>Medium</i>
en/volunteer.wml  198) <br />
en/volunteer.wml  199) Likely Mentors: <i>Roger, Nick, Mike</i>
en/volunteer.wml  200) <br />
en/volunteer.wml  201) It would be great to set up an automated system for tracking network
en/volunteer.wml  202) health over time, graphing it, etc. Part of this project would involve
en/volunteer.wml  203) inventing better metrics for assessing network health and growth. Is the
en/volunteer.wml  204) average uptime of the network increasing? How many relays are qualifying
en/volunteer.wml  205) for Guard status this month compared to last month? What's the turnover
en/volunteer.wml  206) in terms of new relays showing up and relays shutting off? Periodically
en/volunteer.wml  207) people collect brief snapshots, but where it gets really interesting is
en/volunteer.wml  208) when we start tracking data points over time.
en/volunteer.wml  209) <br />
en/volunteer.wml  210) Data could be collected from the "Tor Node Scanner" item above, from
en/volunteer.wml  211) the server descriptors that each relay publishes, and from other
en/volunteer.wml  212) sources. Results over time could be integrated into one of the <a
en/volunteer.wml  213) href="https://torstatus.blutmagie.de/">Tor Status</a> web pages, or be
en/volunteer.wml  214) kept separate. Speaking of the Tor Status pages, take a look at Roger's
en/volunteer.wml  215) <a href="http://archives.seul.org/or/talk/Jan-2008/msg00300.html">Tor
en/volunteer.wml  216) Status wish list</a>.
en/volunteer.wml  217) </li>
en/volunteer.wml  218) 
en/volunteer.wml  219) <li>
en/volunteer.wml  220) <b>Tor path selection improvements</b>
en/volunteer.wml  221) <br />
en/volunteer.wml  222) Priority: <i>High</i>
en/volunteer.wml  223) <br />
en/volunteer.wml  224) Effort Level: <i>Low to Medium</i>
en/volunteer.wml  225) <br />
en/volunteer.wml  226) Skill Level: <i>High</i>
en/volunteer.wml  227) <br />
en/volunteer.wml  228) Likely Mentors: <i>Roger, Nick, Mike</i>
en/volunteer.wml  229) <br />

en/volunteer.wml  230) Applications as of 1 Apr 00:00 UTC: <i>3</i>

en/volunteer.wml  231) <br />

en/volunteer.wml  232) Some simple improvements can be made to Tor's path selection to vastly
en/volunteer.wml  233) improve Tor speed. For instance, some of the (unofficial) <a
en/volunteer.wml  234) href="http://wiki.noreply.org/noreply/TheOnionRouter/FireFoxTorPerf">Tor
en/volunteer.wml  235) Performance Recommendations</a> on the wiki are to increase the number of
en/volunteer.wml  236) guards and decrease the CircuitBuildTimeout. Ideally, the client would
en/volunteer.wml  237) <a href="http://archives.seul.org/or/talk/Feb-2008/msg00012.html">learn
en/volunteer.wml  238) these values by gathering statistics on circuit construction
en/volunteer.wml  239) time</a> (and/or using values gained from Torflow), and set the timeouts
en/volunteer.wml  240) low enough such that some high percentile (75%, 90%, 1-stddev?) of
en/volunteer.wml  241) circuits succeed, yet extremely slow nodes are avoided. This would
en/volunteer.wml  242) involve some statistics gathering+basic research, and some changes to
en/volunteer.wml  243) Tor path selection code.
en/volunteer.wml  244) <br />
en/volunteer.wml  245) In addition, to improve path security, some elements from the <a
en/volunteer.wml  246) href="http://www.torproject.org/svn/trunk/doc/spec/proposals/115-two-hop-paths.txt">Two
en/volunteer.wml  247) Hop Paths proposal</a> could be done as part of this (since it will
en/volunteer.wml  248) likely touch the same code anyways), regardless of the adoption of
en/volunteer.wml  249) that proposal. In particular, clients probably should avoid guards that
en/volunteer.wml  250) seem to fail an excessive percentage of their circuits through them,
en/volunteer.wml  251) and non-firewalled clients should issue a warning if they are only able
en/volunteer.wml  252) to connect to a limited set of guard nodes. See also
en/volunteer.wml  253) <a href="http://archives.seul.org/or/dev/Feb-2008/msg00003.html">this
en/volunteer.wml  254) or-dev post</a>.

en/volunteer.wml  255) </li>
en/volunteer.wml  256) 
en/volunteer.wml  257) <li>

en/volunteer.wml  258) <b>Translation Wiki</b>
en/volunteer.wml  259) <br />
en/volunteer.wml  260) Priority: <i>High</i>
en/volunteer.wml  261) <br />
en/volunteer.wml  262) Effort Level: <i>Medium</i>
en/volunteer.wml  263) <br />
en/volunteer.wml  264) Skill Level: <i>Medium</i>
en/volunteer.wml  265) <br />
en/volunteer.wml  266) Likely Mentors: <i>Jacob</i>
en/volunteer.wml  267) <br />
en/volunteer.wml  268) We need a way to edit and translate sections of the website. Currently
en/volunteer.wml  269) the website is made up of a bunch of <a href="<svnwebsite>en/">wml
en/volunteer.wml  270) files</a>, and <a href="<page translation>">translators</a> fetch these
en/volunteer.wml  271) wml files, translate them in an editor, and either send us the translation
en/volunteer.wml  272) or use svn to commit them back. The current "cost" of publication of
en/volunteer.wml  273) website changes is quite high even for English language users. For a
en/volunteer.wml  274) single word change or any type of
en/volunteer.wml  275) minor change, the page may never be corrected or translated. It would
en/volunteer.wml  276) be nice to have a wiki that was specifically geared towards translation
en/volunteer.wml  277) and would somehow track the upstream (English) versions to indicate when
en/volunteer.wml  278) a fresh translation is needed, like our current
en/volunteer.wml  279) <a href="<page translation-status>">translation status page</a>. This
en/volunteer.wml  280) seems mostly like a job for a wiki
en/volunteer.wml  281) integrator or wiki software author. Certainly the person would need to
en/volunteer.wml  282) be interested in human languages and translation. They should at least
en/volunteer.wml  283) be minimally familiar with what Tor is; but they would not have to interact
en/volunteer.wml  284) with the software, only the documentation and the website.
en/volunteer.wml  285) </li>
en/volunteer.wml  286) 
en/volunteer.wml  287) <li>
en/volunteer.wml  288) <b>Better Debian/Ubuntu Packaging for Tor+Vidalia</b>

en/volunteer.wml  289) <br />

en/volunteer.wml  290) Priority: <i>High</i>
en/volunteer.wml  291) <br />
en/volunteer.wml  292) Effort Level: <i>Medium</i>
en/volunteer.wml  293) <br />
en/volunteer.wml  294) Skill Level: <i>Medium</i>
en/volunteer.wml  295) <br />

en/volunteer.wml  296) Likely Mentors: <i>Peter, Matt</i>

en/volunteer.wml  297) <br />

en/volunteer.wml  298) Applications as of 1 Apr 00:00 UTC: <i>1</i>

en/volunteer.wml  299) <br />

en/volunteer.wml  300) Vidalia currently doesn't play nicely on Debian and Ubuntu with the
en/volunteer.wml  301) default Tor packages. The current Tor packages automatically start Tor
en/volunteer.wml  302) as a daemon running as the debian-tor user and (sensibly) do not have a

en/volunteer.wml  303) <a href="<svnsandbox>doc/spec/control-spec.txt">ControlPort</a> defined
en/volunteer.wml  304) in the default torrc. Consequently, Vidalia will try

en/volunteer.wml  305) to start its own Tor process since it could not connect to the existing

en/volunteer.wml  306) Tor, and Vidalia's Tor process will then exit with an error message

en/volunteer.wml  307) the user likely doesn't understand since Tor cannot bind its listening

en/volunteer.wml  308) ports — they're already in use by the original Tor daemon.

en/volunteer.wml  309) <br />
en/volunteer.wml  310) The current solution involves either telling the user to stop the
en/volunteer.wml  311) existing Tor daemon and let Vidalia start its own Tor process, or
en/volunteer.wml  312) explaining to the user how to set a control port and password in their
en/volunteer.wml  313) torrc. A better solution on Debian would be to use Tor's ControlSocket,
en/volunteer.wml  314) which allows Vidalia to talk to Tor via a Unix domain socket, and could
en/volunteer.wml  315) possibly be enabled by default in Tor's Debian packages. Vidalia can

en/volunteer.wml  316) then authenticate to Tor using filesystem-based (cookie) authentication
en/volunteer.wml  317) if the user running Vidalia is also in the debian-tor group.

en/volunteer.wml  318) <br />
en/volunteer.wml  319) This project will first involve adding support for Tor's ControlSocket
en/volunteer.wml  320) to Vidalia. The student will then develop and test Debian and Ubuntu
en/volunteer.wml  321) packages for Vidalia that conform to Debian's packaging standards and

en/volunteer.wml  322) make sure they work well with the existing Tor packages. We can also

en/volunteer.wml  323) set up an apt repository to host the new Vidalia packages.
en/volunteer.wml  324) <br />

en/volunteer.wml  325) The next challenge would be to find an intuitive usable way for Vidalia
en/volunteer.wml  326) to be able to change Tor's configuration (torrc) even though it is
en/volunteer.wml  327) located in <code>/etc/tor/torrc</code> and thus immutable. The best
en/volunteer.wml  328) idea we've come up with so far is to feed Tor a new configuration via
en/volunteer.wml  329) the ControlSocket when Vidalia starts, but that's bad because Tor starts

en/volunteer.wml  330) each boot with a different configuration than the user wants. The second
en/volunteer.wml  331) best idea

en/volunteer.wml  332) we've come up with is for Vidalia to write out a temporary torrc file
en/volunteer.wml  333) and ask the user to manually move it to <code>/etc/tor/torrc</code>,
en/volunteer.wml  334) but that's bad because users shouldn't have to mess with files directly.
en/volunteer.wml  335) <br />

en/volunteer.wml  336) A student undertaking this project should have prior knowledge of
en/volunteer.wml  337) Debian package management and some C++ development experience. Previous
en/volunteer.wml  338) experience with Qt is helpful, but not required.
en/volunteer.wml  339) </li>
en/volunteer.wml  340) 

en/volunteer.wml  341) <li>
en/volunteer.wml  342) <b>Improving Tor's ability to resist censorship</b>
en/volunteer.wml  343) <br />
en/volunteer.wml  344) Priority: <i>High</i>
en/volunteer.wml  345) <br />
en/volunteer.wml  346) Effort Level: <i>High</i>
en/volunteer.wml  347) <br />
en/volunteer.wml  348) Skill Level: <i>High</i>
en/volunteer.wml  349) <br />
en/volunteer.wml  350) Likely Mentors: <i>Nick</i>
en/volunteer.wml  351) <br />
en/volunteer.wml  352) The Tor 0.2.0.x series makes <a
en/volunteer.wml  353) href="<svnsandbox>doc/design-paper/blocking.html">significant
en/volunteer.wml  354) improvements</a> in resisting national and organizational censorship.
en/volunteer.wml  355) But Tor still needs better mechanisms for some parts of its
en/volunteer.wml  356) anti-censorship design.  For example, current Tors can only listen on a
en/volunteer.wml  357) single address/port combination at a time.  There's
en/volunteer.wml  358) <a href="<svnsandbox>doc/spec/proposals/118-multiple-orports.txt">a
en/volunteer.wml  359) proposal to address this limitation</a> and allow clients to connect
en/volunteer.wml  360) to any given Tor on multiple addresses and ports, but it needs more
en/volunteer.wml  361) work.  Another anti-censorship project (far more difficult) is to try
en/volunteer.wml  362) to make Tor more scanning-resistant.  Right now, an adversary can identify
en/volunteer.wml  363) <a href="<svnsandbox>doc/spec/proposals/125-bridges.txt">Tor bridges</a>
en/volunteer.wml  364) just by trying to connect to them, following the Tor protocol, and
en/volunteer.wml  365) seeing if they respond.  To solve this, bridges could
en/volunteer.wml  366) <a href="<svnsandbox>doc/design-paper/blocking.html#tth_sEc9.3">act like
en/volunteer.wml  367) webservers</a> (HTTP or HTTPS) when contacted by port-scanning tools,
en/volunteer.wml  368) and not act like bridges until the user provides a bridge-specific key.
en/volunteer.wml  369) <br />
en/volunteer.wml  370) This project involves a lot of research and design. One of the big
en/volunteer.wml  371) challenges will be identifying and crafting approaches that can still
en/volunteer.wml  372) resist an adversary even after the adversary knows the design, and
en/volunteer.wml  373) then trading off censorship resistance with usability and robustness.
en/volunteer.wml  374) </li>
en/volunteer.wml  375) 
en/volunteer.wml  376) <li>
en/volunteer.wml  377) <b>Tor/Polipo/Vidalia Auto-Update Framework</b>
en/volunteer.wml  378) <br />
en/volunteer.wml  379) Priority: <i>Medium</i>
en/volunteer.wml  380) <br />
en/volunteer.wml  381) Effort Level: <i>High</i>
en/volunteer.wml  382) <br />
en/volunteer.wml  383) Skill Level: <i>High</i>
en/volunteer.wml  384) <br />
en/volunteer.wml  385) Likely Mentors: <i>Matt, Jacob</i>
en/volunteer.wml  386) <br />
en/volunteer.wml  387) We're in need of a good authenticated-update framework.
en/volunteer.wml  388) Vidalia already has the ability to notice when the user is running an
en/volunteer.wml  389) outdated or unrecommended version of Tor, using signed statements inside
en/volunteer.wml  390) the Tor directory information. Currently, Vidalia simply pops
en/volunteer.wml  391) up a little message box that lets the user know they should manually
en/volunteer.wml  392) upgrade. The goal of this project would be to extend Vidalia with the
en/volunteer.wml  393) ability to also fetch and install the updated Tor software for the
en/volunteer.wml  394) user. We should do the fetches via Tor when possible, but also fall back
en/volunteer.wml  395) to direct fetches in a smart way. Time permitting, we would also like
en/volunteer.wml  396) to be able to update other
en/volunteer.wml  397) applications included in the bundled installers, such as Polipo and
en/volunteer.wml  398) Vidalia itself.
en/volunteer.wml  399) <br />
en/volunteer.wml  400) To complete this project, the student will first need to first investigate
en/volunteer.wml  401) the existing auto-update frameworks (e.g., Sparkle on OS X) to evaluate
en/volunteer.wml  402) their strengths, weaknesses, security properties, and ability to be
en/volunteer.wml  403) integrated into Vidalia. If none are found to be suitable, the student
en/volunteer.wml  404) will design their own auto-update framework, document the design, and
en/volunteer.wml  405) then discuss the design with other developers to assess any security
en/volunteer.wml  406) issues. The student will then implement their framework (or integrate
en/volunteer.wml  407) an existing one) and test it.
en/volunteer.wml  408) <br />
en/volunteer.wml  409) A student undertaking this project should have good C++ development
en/volunteer.wml  410) experience. Previous experience with Qt is helpful, but not required. The
en/volunteer.wml  411) student should also have a good understanding of common security
en/volunteer.wml  412) practices, such as package signature verification. Good writing ability
en/volunteer.wml  413) is also important for this project, since a vital step of the project
en/volunteer.wml  414) will be producing a design document for others to review and discuss
en/volunteer.wml  415) with the student prior to implementation.
en/volunteer.wml  416) </li>
en/volunteer.wml  417) 
en/volunteer.wml  418) <li>
en/volunteer.wml  419) <b>An Improved and More Usable Network Map in Vidalia</b>
en/volunteer.wml  420) <br />
en/volunteer.wml  421) Priority: <i>Medium</i>
en/volunteer.wml  422) <br />
en/volunteer.wml  423) Effort Level: <i>Medium</i>
en/volunteer.wml  424) <br />
en/volunteer.wml  425) Skill Level: <i>Medium to High</i>
en/volunteer.wml  426) <br />
en/volunteer.wml  427) Likely Mentors: <i>Matt</i>
en/volunteer.wml  428) <br />
en/volunteer.wml  429) One of Vidalia's existing features is a network map that shows the user
en/volunteer.wml  430) the approximate geographic location of relays in the Tor network and
en/volunteer.wml  431) plots the paths the user's traffic takes as it is tunneled through the
en/volunteer.wml  432) Tor network. The map is currently not very interactive and has rather
en/volunteer.wml  433) poor graphics. Instead, we would like to leverage KDE's Marble widget
en/volunteer.wml  434) that gives us a better quality map and enables improved interactivity,
en/volunteer.wml  435) such as allowing the user to click on individual relays or circuits to
en/volunteer.wml  436) display additional information. We might also consider adding the ability
en/volunteer.wml  437) for users to click on a particular relay or a country containing one or
en/volunteer.wml  438) more Tor exit relays and say, "I want my connections to foo.com to exit
en/volunteer.wml  439) from here."
en/volunteer.wml  440) <br />
en/volunteer.wml  441) This project will first involve the student getting familiar with Vidalia
en/volunteer.wml  442) and the Marble widget's API. The student will then integrate the widget
en/volunteer.wml  443) into Vidalia and customize Marble to be better suited for our application,
en/volunteer.wml  444) such as making circuits clickable, storing cached map data in Vidalia's
en/volunteer.wml  445) own data directory, and customizing some of the widget's dialogs.
en/volunteer.wml  446) <br />
en/volunteer.wml  447) A student undertaking this project should have good C++ development
en/volunteer.wml  448) experience. Previous experience with Qt and CMake is helpful, but not
en/volunteer.wml  449) required.
en/volunteer.wml  450) </li>
en/volunteer.wml  451) 

en/volunteer.wml  452) <li>

en/volunteer.wml  453) <b>Tor Controller Status Event Interface</b>

en/volunteer.wml  454) <br />

en/volunteer.wml  455) Priority: <i>Medium</i>
en/volunteer.wml  456) <br />
en/volunteer.wml  457) Effort Level: <i>Medium</i>
en/volunteer.wml  458) <br />
en/volunteer.wml  459) Skill Level: <i>Medium</i>
en/volunteer.wml  460) <br />

en/volunteer.wml  461) Likely Mentors: <i>Matt, Roger</i>

en/volunteer.wml  462) <br />

en/volunteer.wml  463) There are a number of status changes inside Tor of which the user may need

en/volunteer.wml  464) to be informed. For example, if the user is trying to set up his Tor as a
en/volunteer.wml  465) relay and Tor decides that its ports are not reachable from outside

en/volunteer.wml  466) the user's network, we should alert the user. Currently, all the user

en/volunteer.wml  467) gets is a couple log messages in Vidalia's 'message log' window, which they

en/volunteer.wml  468) likely never see since they don't receive a notification that something
en/volunteer.wml  469) has gone wrong. Even if the user does actually look at the message log,
en/volunteer.wml  470) most of the messages make little sense to the novice user.
en/volunteer.wml  471) <br />
en/volunteer.wml  472) Tor has the ability to inform Vidalia of many such status changes, and
en/volunteer.wml  473) we recently implemented support for a couple of these events. Still,
en/volunteer.wml  474) there are many more status events the user should be informed of and we
en/volunteer.wml  475) need a better UI for actually displaying them to the user.
en/volunteer.wml  476) <br />
en/volunteer.wml  477) The goal of this project then is to design and implement a UI for
en/volunteer.wml  478) displaying Tor status events to the user. For example, we might put a
en/volunteer.wml  479) little badge on Vidalia's tray icon that alerts the user to new status
en/volunteer.wml  480) events they should look at. Double-clicking the icon could bring up a
en/volunteer.wml  481) dialog that summarizes recent status events in simple terms and maybe

en/volunteer.wml  482) suggests a remedy for any negative events if they can be corrected by

en/volunteer.wml  483) the user. Of course, this is just an example and the student is free to
en/volunteer.wml  484) suggest another approach.
en/volunteer.wml  485) <br />
en/volunteer.wml  486) A student undertaking this project should have good UI design and layout

en/volunteer.wml  487) and some C++ development experience. Previous experience with Qt and

en/volunteer.wml  488) Qt's Designer will be very helpful, but are not required. Some

en/volunteer.wml  489) English writing ability will also be useful, since this project will
en/volunteer.wml  490) likely involve writing small amounts of help documentation that should
en/volunteer.wml  491) be understandable by non-technical users. Bonus points for some graphic
en/volunteer.wml  492) design/Photoshop fu, since we might want/need some shiny new icons too.
en/volunteer.wml  493) </li>
en/volunteer.wml  494) 

en/volunteer.wml  495) <li>

en/volunteer.wml  496) <b>Improvements on our active browser configuration tester</b> -

en/volunteer.wml  497) <a href="https://check.torproject.org/">https://check.torproject.org/</a>

en/volunteer.wml  498) <br />

en/volunteer.wml  499) Priority: <i>Medium</i>
en/volunteer.wml  500) <br />
en/volunteer.wml  501) Effort Level: <i>Low</i>
en/volunteer.wml  502) <br />
en/volunteer.wml  503) Skill Level: <i>Low to Medium</i>
en/volunteer.wml  504) <br />

en/volunteer.wml  505) Likely Mentors: <i>Jacob, Steven</i>

en/volunteer.wml  506) <br />

en/volunteer.wml  507) Applications as of 1 Apr 00:00 UTC: <i>1</i>
en/volunteer.wml  508) <br />

en/volunteer.wml  509) We currently have a functional web page to detect if Tor is working. It

en/volunteer.wml  510) has a few places where it falls short. It requires improvements with

en/volunteer.wml  511) regard to default languages and functionality. It currently only responds
en/volunteer.wml  512) in English. In addition, it is a hack of a perl script that should have
en/volunteer.wml  513) never seen the light of day. It should probably be rewritten in python

en/volunteer.wml  514) with multi-lingual support in mind. It currently uses the <a
en/volunteer.wml  515) href="http://exitlist.torproject.org/">Tor DNS exit list</a>
en/volunteer.wml  516) and should continue to do so in the future. It currently result in certain

en/volunteer.wml  517) false positives and these should be discovered, documented, and fixed
en/volunteer.wml  518) where possible. Anyone working on this project should be interested in

en/volunteer.wml  519) DNS, basic perl or preferably python programming skills, and will have

en/volunteer.wml  520) to interact minimally with Tor to test their code.

en/volunteer.wml  521) <br />
en/volunteer.wml  522) If you want to make the project more exciting
en/volunteer.wml  523) and involve more design and coding, take a look at <a
en/volunteer.wml  524) href="<svnsandbox>doc/spec/proposals/131-verify-tor-usage.txt">proposal
en/volunteer.wml  525) 131-verify-tor-usage.txt</a>.

en/volunteer.wml  526) </li>
en/volunteer.wml  527) 
en/volunteer.wml  528) <li>

en/volunteer.wml  529) <b>Improvements on our DNS Exit List service</b> -

en/volunteer.wml  530) <a href="http://exitlist.torproject.org/">http://exitlist.torproject.org/</a>

en/volunteer.wml  531) <br />

en/volunteer.wml  532) Priority: <i>Medium</i>
en/volunteer.wml  533) <br />
en/volunteer.wml  534) Effort Level: <i>Low</i>
en/volunteer.wml  535) <br />
en/volunteer.wml  536) Skill Level: <i>Low</i>
en/volunteer.wml  537) <br />

en/volunteer.wml  538) Likely Mentors: <i>Jacob, Tup</i>

en/volunteer.wml  539) <br />

en/volunteer.wml  540) The <a href="http://p56soo2ibjkx23xo.onion/">exitlist software</a>
en/volunteer.wml  541) is written by our fabulous anonymous

en/volunteer.wml  542) contributer Tup. It's a DNS server written in Haskell that supports part of our <a

en/volunteer.wml  543) href="https://www.torproject.org/svn/trunk/doc/contrib/torel-design.txt">exitlist

en/volunteer.wml  544) design document</a>. Currently, it is functional and it is used by

en/volunteer.wml  545) check.torproject.org and other users. The issues that are outstanding
en/volunteer.wml  546) are mostly aesthetic. This wonderful service could use a much better
en/volunteer.wml  547) website using the common Tor theme. It would be best served with better
en/volunteer.wml  548) documentation for common services that use an RBL. It could use more
en/volunteer.wml  549) publicity. A person working on this project should be interested in DNS,
en/volunteer.wml  550) basic RBL configuration for popular services, and writing documentation.
en/volunteer.wml  551) The person would require minimal Tor interaction — testing their
en/volunteer.wml  552) own documentation at the very least. Furthermore, it would be useful

en/volunteer.wml  553) if they were interested in Haskell and wanted to implement more of the

en/volunteer.wml  554) torel-design.txt suggestions.
en/volunteer.wml  555) </li>
en/volunteer.wml  556) 
en/volunteer.wml  557) <li>

en/volunteer.wml  558) <b>Testing integration of Tor with web browsers for our end users</b>

en/volunteer.wml  559) <br />

en/volunteer.wml  560) Priority: <i>Medium</i>
en/volunteer.wml  561) <br />
en/volunteer.wml  562) Effort Level: <i>Medium</i>
en/volunteer.wml  563) <br />
en/volunteer.wml  564) Skill Level: <i>Medium</i>
en/volunteer.wml  565) <br />

en/volunteer.wml  566) Likely Mentors: <i>Jacob, Mike, Greg</i>

en/volunteer.wml  567) <br />

en/volunteer.wml  568) Applications as of 1 Apr 00:00 UTC: <i>1</i>
en/volunteer.wml  569) <br />

en/volunteer.wml  570) The Tor project currently lacks a solid test suite to ensure that a
en/volunteer.wml  571) user has a properly and safely configured web browser. It should test for as

en/volunteer.wml  572) many known issues as possible. It should attempt to decloak the

en/volunteer.wml  573) user in any way possible. Two current webpages that track these

en/volunteer.wml  574) kinds of issues are run by Greg Fleischer and HD Moore. Greg keeps a nice <a

en/volunteer.wml  575) href="http://pseudo-flaw.net/tor/torbutton/">list of issues along
en/volunteer.wml  576) with their proof of concept code, bug issues, etc</a>. HD Moore runs

en/volunteer.wml  577) the <a href="http://metasploit.com/research/projects/decloak/">metasploit

en/volunteer.wml  578) decloak website</a>. A student interested in defending Tor could start

en/volunteer.wml  579) by collecting as many workable and known methods for decloaking a

en/volunteer.wml  580) Tor user. (<a href="https://torcheck.xenobite.eu/">This page</a> may
en/volunteer.wml  581) be helpful as a start.) The student should be familiar with the common
en/volunteer.wml  582) pitfalls but

en/volunteer.wml  583) possibly have new methods in mind for implementing decloaking issues. The
en/volunteer.wml  584) website should ensure that it tells a user what their problem is. It
en/volunteer.wml  585) should help them to fix the problem or direct them to the proper support

en/volunteer.wml  586) channels. The student should be closely familiar with using Tor and how
en/volunteer.wml  587) to prevent Tor information leakage.

en/volunteer.wml  588) </li>
en/volunteer.wml  589) 

en/volunteer.wml  590) <li>

en/volunteer.wml  591) <b>Libevent and Tor integration improvements</b>
en/volunteer.wml  592) <br />

en/volunteer.wml  593) Priority: <i>Medium</i>
en/volunteer.wml  594) <br />
en/volunteer.wml  595) Effort Level: <i>High</i>
en/volunteer.wml  596) <br />
en/volunteer.wml  597) Skill Level: <i>Medium to High</i>
en/volunteer.wml  598) <br />

en/volunteer.wml  599) Likely Mentors: <i>Nick</i>

en/volunteer.wml  600) <br />

en/volunteer.wml  601) Tor should make better use of the more recent features of Niels
en/volunteer.wml  602) Provos's <a href="http://monkey.org/~provos/libevent/">Libevent</a>

en/volunteer.wml  603) library.  Tor already uses Libevent for its low-level asynchronous IO

en/volunteer.wml  604) calls, and could also use Libevent's increasingly good implementations

en/volunteer.wml  605) of network buffers and of HTTP.  This wouldn't be simply a matter of

en/volunteer.wml  606) replacing Tor's internal calls with calls to Libevent: instead, we'll

en/volunteer.wml  607) need to refactor Tor to use Libevent calls that do not follow the

en/volunteer.wml  608) same models as Tor's existing backends. Also, we'll need to add
en/volunteer.wml  609) missing functionality to Libevent as needed — most difficult likely
en/volunteer.wml  610) will be adding OpenSSL support on top of Libevent's buffer abstraction.
en/volunteer.wml  611) Also tricky will be adding rate-limiting to Libevent.

en/volunteer.wml  612) </li>
en/volunteer.wml  613) 
en/volunteer.wml  614) <li>

en/volunteer.wml  615) <b>Tuneup Tor!</b>
en/volunteer.wml  616) <br />

en/volunteer.wml  617) Priority: <i>Medium</i>
en/volunteer.wml  618) <br />
en/volunteer.wml  619) Effort Level: <i>Medium</i>
en/volunteer.wml  620) <br />
en/volunteer.wml  621) Skill Level: <i>Medium to High</i>
en/volunteer.wml  622) <br />

en/volunteer.wml  623) Likely Mentors: <i>Nick, Roger, Mike</i>

en/volunteer.wml  624) <br />

en/volunteer.wml  625) Right now, Tor relays measure and report their own bandwidth, and Tor
en/volunteer.wml  626) clients choose which relays to use in part based on that bandwidth.
en/volunteer.wml  627) This approach is vulnerable to
en/volunteer.wml  628) <a href="http://freehaven.net/anonbib/#bauer:wpes2007">attacks where
en/volunteer.wml  629) relays lie about their bandwidth</a>;
en/volunteer.wml  630) to address this, Tor currently caps the maximum bandwidth
en/volunteer.wml  631) it's willing to believe any relay provides.  This is a limited fix, and
en/volunteer.wml  632) a waste of bandwidth capacity to boot.  Instead,

en/volunteer.wml  633) Tor should possibly measure bandwidth in a more distributed way, perhaps
en/volunteer.wml  634) as described in the

en/volunteer.wml  635) <a href="http://freehaven.net/anonbib/author.html#snader08">"A Tune-up for
en/volunteer.wml  636) Tor"</a> paper

en/volunteer.wml  637) by Snader and Borisov. A student could use current testing code to

en/volunteer.wml  638) double-check this paper's findings and verify the extent to which they

en/volunteer.wml  639) dovetail with Tor as deployed in the wild, and determine good ways to
en/volunteer.wml  640) incorporate them into their suggestions Tor network without adding too

en/volunteer.wml  641) much communications overhead between relays and directory

en/volunteer.wml  642) authorities.

en/volunteer.wml  643) </li>
en/volunteer.wml  644) 

en/volunteer.wml  645) <!--

en/volunteer.wml  646) <li>

en/volunteer.wml  647) <b>Improving the Tor QA process: Continuous Integration for Windows builds</b>
en/volunteer.wml  648) <br />

en/volunteer.wml  649) Priority: <i>High</i>
en/volunteer.wml  650) <br />
en/volunteer.wml  651) Effort Level: <i>Medium</i>
en/volunteer.wml  652) <br />
en/volunteer.wml  653) Skill Level: <i>Medium</i>
en/volunteer.wml  654) <br />

en/volunteer.wml  655) Likely Mentors: <i>Jacob, Andrew</i>

en/volunteer.wml  656) <br />

en/volunteer.wml  657) It would be useful to have automated build processes for Windows and
en/volunteer.wml  658) probably other platforms. The purpose of having a continuous integration
en/volunteer.wml  659) build environment is to ensure that Windows isn't left behind for any of
en/volunteer.wml  660) the software projects used in the Tor project or its accompanying.<br />
en/volunteer.wml  661) Buildbot may be a good choice for this as it appears to support all of

en/volunteer.wml  662) the platforms Tor does. See the

en/volunteer.wml  663) <a href="http://en.wikipedia.org/wiki/BuildBot">wikipedia entry for

en/volunteer.wml  664) buildbot</a>.<br />
en/volunteer.wml  665) There may be better options and the person undertaking this task should
en/volunteer.wml  666) evaluate other options. Any person working on this automatic build
en/volunteer.wml  667) process should have experience or be willing to learn how to build all
en/volunteer.wml  668) of the respective Tor related code bases from scratch. Furthermore, the
en/volunteer.wml  669) person should have some experience building software in Windows
en/volunteer.wml  670) environments as this is the target audience we want to ensure we do not
en/volunteer.wml  671) leave behind. It would require close work with the Tor source code but

en/volunteer.wml  672) probably only in the form of building, not authoring.<br />
en/volunteer.wml  673) Additionally, we need to automate our performance testing for all platforms.

en/volunteer.wml  674) We've got buildbot (except on Windows — as noted above) to automate

en/volunteer.wml  675) our regular integration and compile testing already,
en/volunteer.wml  676) but we need to get our network simulation tests (as built in torflow)
en/volunteer.wml  677) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml  678) network either on a single machine, or across several, so we can test

en/volunteer.wml  679) changes in performance on machines in different roles automatically.

en/volunteer.wml  680) </li>

en/volunteer.wml  681) -->

en/volunteer.wml  682) 

en/volunteer.wml  683) <li>

en/volunteer.wml  684) <b>Improve our unit testing process</b>
en/volunteer.wml  685) <br />

en/volunteer.wml  686) Priority: <i>Medium</i>
en/volunteer.wml  687) <br />
en/volunteer.wml  688) Effort Level: <i>Medium</i>
en/volunteer.wml  689) <br />
en/volunteer.wml  690) Skill Level: <i>Medium</i>
en/volunteer.wml  691) <br />

en/volunteer.wml  692) Likely Mentors: <i>Nick</i>

en/volunteer.wml  693) <br />

en/volunteer.wml  694) Tor needs to be far more tested. This is a multi-part effort. To start

en/volunteer.wml  695) with, our unit test coverage should rise substantially, especially in

en/volunteer.wml  696) the areas outside the utility functions. This will require significant

en/volunteer.wml  697) refactoring of some parts of Tor, in order to dissociate as much logic

en/volunteer.wml  698) as possible from globals.
en/volunteer.wml  699) <br />

en/volunteer.wml  700) Additionally, we need to automate our performance testing. We've got

en/volunteer.wml  701) buildbot to automate our regular integration and compile testing already
en/volunteer.wml  702) (though we need somebody to set it up on Windows),
en/volunteer.wml  703) but we need to get our network simulation tests (as built in TorFlow: see
en/volunteer.wml  704) the "Tor Node Scanner improvements" item)

en/volunteer.wml  705) updated for more recent versions of Tor, and designed to launch a test
en/volunteer.wml  706) network either on a single machine, or across several, so we can test

en/volunteer.wml  707) changes in performance on machines in different roles automatically.

en/volunteer.wml  708) </li>
en/volunteer.wml  709) 

en/volunteer.wml  710) <li>

en/volunteer.wml  711) <b>Help revive an independent Tor client implementation</b>

en/volunteer.wml  712) <br />

en/volunteer.wml  713) Priority: <i>Medium</i>

en/volunteer.wml  714) <br />
en/volunteer.wml  715) Effort Level: <i>High</i>
en/volunteer.wml  716) <br />
en/volunteer.wml  717) Skill Level: <i>Medium to High</i>
en/volunteer.wml  718) <br />

en/volunteer.wml  719) Likely Mentors: <i>Karsten, Nick</i>

en/volunteer.wml  720) <br />

en/volunteer.wml  721) Applications as of 1 Apr 00::00 UTC: <i>4</i>

en/volunteer.wml  722) <br />

en/volunteer.wml  723) Reanimate one of the approaches to implement a Tor client in Java,
en/volunteer.wml  724) e.g. the <a href="http://onioncoffee.sourceforge.net/">OnionCoffee
en/volunteer.wml  725) project</a>, and make it run on <a
en/volunteer.wml  726) href="http://code.google.com/android/">Android</a>. The first step
en/volunteer.wml  727) would be to port the existing code and execute it in an Android
en/volunteer.wml  728) environment. Next, the code should be updated to support the newer Tor
en/volunteer.wml  729) protocol versions like the <a href="<svnsandbox>doc/spec/dir-spec.txt">v3
en/volunteer.wml  730) directory protocol</a>. Further, support for requesting or even

en/volunteer.wml  731) providing Tor hidden services would be neat, but not required.
en/volunteer.wml  732) <br />
en/volunteer.wml  733) The student should be able to understand and write new Java code, including

en/volunteer.wml  734) a Java cryptography API. Being able to read C code would be helpful,

en/volunteer.wml  735) too. The student should be willing to read the existing documentation,

en/volunteer.wml  736) implement code based on it, and refine the documentation
en/volunteer.wml  737) when things are underdocumented. This project is mostly about coding and

en/volunteer.wml  738) to a small degree about design.
en/volunteer.wml  739) </li>
en/volunteer.wml  740) 
en/volunteer.wml  741) <li>

en/volunteer.wml  742) <b>Automatic system tests and automatically starting private Tor networks</b>

en/volunteer.wml  743) <br />

en/volunteer.wml  744) Priority: <i>Medium</i>
en/volunteer.wml  745) <br />
en/volunteer.wml  746) Effort Level: <i>Medium</i>
en/volunteer.wml  747) <br />
en/volunteer.wml  748) Skill Level: <i>Medium</i>
en/volunteer.wml  749) <br />

en/volunteer.wml  750) Likely Mentors: <i>Karsten, Nick, Roger</i>

en/volunteer.wml  751) <br />

en/volunteer.wml  752) Applications as of 1 Apr 00:00 UTC: <i>2</i>
en/volunteer.wml  753) <br />

en/volunteer.wml  754) Write a tool that runs automatic system tests in addition
en/volunteer.wml  755) to the existing unit tests. The Java-based Tor simulator <a
en/volunteer.wml  756) href="https://tor-svn.freehaven.net/svn/puppetor/trunk/">PuppeTor</a>
en/volunteer.wml  757) might be a good start for starting up a private Tor network, using it
en/volunteer.wml  758) for a while, and verifying that at least parts of it are working. This
en/volunteer.wml  759) project requires to conceive a blueprint for performing system tests
en/volunteer.wml  760) of private Tor networks, before starting to code. Typical types of
en/volunteer.wml  761) tests range from performing single requests over the private network to
en/volunteer.wml  762) manipulating exchanged messages and see if nodes handle corrupt messages

en/volunteer.wml  763) appropriately.
en/volunteer.wml  764) <br />
en/volunteer.wml  765) The student should be able to obtain a good understanding

en/volunteer.wml  766) of how Tor works and what problems and bugs could arise to design good

en/volunteer.wml  767) test cases. Understanding the existing Tor code structure and documentation is

en/volunteer.wml  768) vital. If PuppeTor is used, the student should also be able to understand
en/volunteer.wml  769) and possibly extend an existing Java application. This project is partly
en/volunteer.wml  770) about design and partly about coding.
en/volunteer.wml  771) </li>
en/volunteer.wml  772) 
en/volunteer.wml  773) <li>

en/volunteer.wml  774) <b>Bring moniTor to life</b>
en/volunteer.wml  775) <br />

en/volunteer.wml  776) Priority: <i>Medium</i>
en/volunteer.wml  777) <br />
en/volunteer.wml  778) Effort Level: <i>Medium</i>
en/volunteer.wml  779) <br />
en/volunteer.wml  780) Skill Level: <i>Low to Medium</i>
en/volunteer.wml  781) <br />

en/volunteer.wml  782) Likely Mentors: <i>Karsten, Jacob</i>

en/volunteer.wml  783) <br />

en/volunteer.wml  784) Applications as of 1 Apr 00::00 UTC: <i>2</i>

en/volunteer.wml  785) <br />

en/volunteer.wml  786) Implement a <a href="http://www.ss64.com/bash/top.html">top-like</a>
en/volunteer.wml  787) management tool for Tor relays. The purpose of such a tool would be
en/volunteer.wml  788) to monitor a local Tor relay via its control port and include useful
en/volunteer.wml  789) system information of the underlying machine. When running this tool, it
en/volunteer.wml  790) would dynamically update its content like top does for Linux processes.
en/volunteer.wml  791) <a href="http://archives.seul.org/or/dev/Jan-2008/msg00005.html">This

en/volunteer.wml  792) or-dev post</a> might be a good first read.
en/volunteer.wml  793) <br />
en/volunteer.wml  794) The student should be familiar

en/volunteer.wml  795) with or willing to learn about administering a Tor relay and configuring
en/volunteer.wml  796) it via its control port. As an initial prototype is written in Python,
en/volunteer.wml  797) some knowledge about writing Python code would be helpful, too. This

en/volunteer.wml  798) project is one part about identifying requirements to such a
en/volunteer.wml  799) tool and designing its interface, and one part lots of coding.

en/volunteer.wml  800) </li>
en/volunteer.wml  801) 

en/volunteer.wml  802) <li>
en/volunteer.wml  803) <b>Torbutton improvements</b>
en/volunteer.wml  804) <br />

en/volunteer.wml  805) Priority: <i>Medium</i>

en/volunteer.wml  806) <br />

en/volunteer.wml  807) Effort Level: <i>High</i>
en/volunteer.wml  808) <br />
en/volunteer.wml  809) Skill Level: <i>High</i>

en/volunteer.wml  810) <br />

en/volunteer.wml  811) Likely Mentors: <i>Mike</i>

en/volunteer.wml  812) <br/>
en/volunteer.wml  813) Torbutton has a number of improvements that can be made in the post-1.2
en/volunteer.wml  814) timeframe. Most of these are documented as feature requests in the <a

en/volunteer.wml  815) href="https://bugs.torproject.org/flyspray/index.php?tasks=all&project=5">Torbutton

en/volunteer.wml  816) flyspray section</a>. Good examples include: stripping off node.exit on http
en/volunteer.wml  817) headers, more fine-grained control over formfill blocking, improved referrer

en/volunteer.wml  818) spoofing based on the domain of the site (a-la <a

en/volunteer.wml  819) href="https://addons.mozilla.org/en-US/firefox/addon/953">refcontrol extension</a>),

en/volunteer.wml  820) tighter integration with Vidalia for reporting Tor status, a New Identity
en/volunteer.wml  821) button with Tor integration and multiple identity management, and anything

en/volunteer.wml  822) else you might think of.

en/volunteer.wml  823) <br />
en/volunteer.wml  824) This work would be independent coding in Javascript and the fun world of <a
en/volunteer.wml  825) href="http://www.mozilla.org/keymaster/gatekeeper/there.is.only.xul">XUL</a>,
en/volunteer.wml  826) with not too much involvement in the Tor internals.

en/volunteer.wml  827) </li>
en/volunteer.wml  828) 

en/volunteer.wml  829) <li>

en/volunteer.wml  830) <b>Porting Polipo to Windows</b>
en/volunteer.wml  831) <br />

en/volunteer.wml  832) Priority: <i>Medium</i>

en/volunteer.wml  833) <br />

en/volunteer.wml  834) Effort Level: <i>Medium</i>

en/volunteer.wml  835) <br />
en/volunteer.wml  836) Skill Level: <i>Medium to High</i>
en/volunteer.wml  837) <br />

en/volunteer.wml  838) Likely Mentors: <i>Andrew, Steven, Roger</i>

en/volunteer.wml  839) <br />

en/volunteer.wml  840) Help port <a
en/volunteer.wml  841) href="http://www.pps.jussieu.fr/~jch/software/polipo/">Polipo</a> to

en/volunteer.wml  842) Windows. Example topics to tackle include:
en/volunteer.wml  843) 1) handle spaces in path names and understand the filesystem
en/volunteer.wml  844) namespace — that is, where application data, personal data,

en/volunteer.wml  845) and program data typically reside in various versions of Windows. 2) the
en/volunteer.wml  846) ability to handle ipv6 communications. 3) the ability to asynchronously
en/volunteer.wml  847) query name servers, find the system nameservers, and manage netbios
en/volunteer.wml  848) and dns queries. 4) use native regex capabilities of Windows, rather
en/volunteer.wml  849) than using 3rd party GNU regex libraries. 5) manage events and buffers
en/volunteer.wml  850) natively (i.e. in Unix-like OSes, Polipo defaults to 25% of ram, in
en/volunteer.wml  851) Windows it's whatever the config specifies). 6) some sort of GUI config
en/volunteer.wml  852) and reporting tool, bonus if it has a systray icon with right clickable
en/volunteer.wml  853) menu options. Double bonus if it's cross-platform compatible.
en/volunteer.wml  854) </li>
en/volunteer.wml  855) 
en/volunteer.wml  856) <li>

en/volunteer.wml  857) <b>Make our diagrams beautiful and automated</b>

en/volunteer.wml  858) <br />

en/volunteer.wml  859) Priority: <i>Medium</i>

en/volunteer.wml  860) <br />
en/volunteer.wml  861) Effort Level: <i>Low</i>
en/volunteer.wml  862) <br />
en/volunteer.wml  863) Skill Level: <i>Low</i>
en/volunteer.wml  864) <br />

en/volunteer.wml  865) Likely Mentors: <i>Andrew</i>

en/volunteer.wml  866) <br />

en/volunteer.wml  867) We need a way to generate the website diagrams (for example, the "How
en/volunteer.wml  868) Tor Works" pictures on the <a href="<page overview>">overview page</a>
en/volunteer.wml  869) from source, so we can translate them as UTF-8 text rather than edit
en/volunteer.wml  870) them by hand with Gimp. We might want to
en/volunteer.wml  871) integrate this as an wml file so translations are easy and images are
en/volunteer.wml  872) generated in multiple languages whenever we build the website. See the
en/volunteer.wml  873) "Translation Wiki" idea above.

en/volunteer.wml  874) </li>
en/volunteer.wml  875) 

en/volunteer.wml  876) <li>
en/volunteer.wml  877) <b>Improve the LiveCD offerings for the Tor community</b>
en/volunteer.wml  878) <br />

en/volunteer.wml  879) Priority: <i>Low</i>
en/volunteer.wml  880) <br />
en/volunteer.wml  881) Effort Level: <i>Low</i>
en/volunteer.wml  882) <br />
en/volunteer.wml  883) Skill Level: <i>Medium to High</i>
en/volunteer.wml  884) <br />

en/volunteer.wml  885) Likely Mentors: <i>Anonym, Jacob, Roger</i>

en/volunteer.wml  886) <br />

en/volunteer.wml  887) How can we make the <a

en/volunteer.wml  888) href="http://anonymityanywhere.com/incognito/">Incognito LiveCD</a>

en/volunteer.wml  889) easier to maintain, improve, and document?
en/volunteer.wml  890) </li>

en/volunteer.wml  891) 

en/volunteer.wml  892) <li>
en/volunteer.wml  893) <b>Rework and extend Blossom</b>
en/volunteer.wml  894) <br />
en/volunteer.wml  895) Priority: <i>Medium</i>
en/volunteer.wml  896) <br />
en/volunteer.wml  897) Effort Level: <i>Medium to High</i>
en/volunteer.wml  898) <br />
en/volunteer.wml  899) Skill Level: <i>Medium to High</i>
en/volunteer.wml  900) <br />
en/volunteer.wml  901) Likely Mentors: <i>Goodell</i>
en/volunteer.wml  902) <br />
en/volunteer.wml  903) Rework and extend Blossom (a tool for monitoring and
en/volunteer.wml  904) selecting appropriate Tor circuits based upon exit node requirements
en/volunteer.wml  905) specified by the user) to gather data in a self-contained way, with
en/volunteer.wml  906) parameters easily configurable by the user.  Blossom is presently
en/volunteer.wml  907) implemented as a single Python script that interfaces with Tor using the
en/volunteer.wml  908) Controller interface and depends upon metadata about Tor nodes obtained
en/volunteer.wml  909) via external processes, such as a webpage indicating status of the nodes
en/volunteer.wml  910) plus publically available data from DNS, whois, etc.  This project has
en/volunteer.wml  911) two parts: (1) Determine which additional metadata may be useful and
en/volunteer.wml  912) rework Blossom so that it cleanly obtains the metadata on its own rather
en/volunteer.wml  913) than depend upon external scripts (this may, for example, involve
en/volunteer.wml  914) additional threads or inter-process communication), and (2) develop a
en/volunteer.wml  915) means by which the user can easily configure Blossom, starting with a
en/volunteer.wml  916) configuration file and possibly working up to a web configuration engine.

en/volunteer.wml  917) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml  918) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml  919) interest in network neutrality is important as well, since the
en/volunteer.wml  920) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml  921) the core of the Blossom effort.

en/volunteer.wml  922) </li>
en/volunteer.wml  923) 
en/volunteer.wml  924) <li>
en/volunteer.wml  925) <b>Improve Blossom: Allow users to qualitatively describe exit nodes they desire</b>
en/volunteer.wml  926) <br />
en/volunteer.wml  927) Priority: <i>Low</i>
en/volunteer.wml  928) <br />
en/volunteer.wml  929) Effort Level: <i>Medium</i>
en/volunteer.wml  930) <br />
en/volunteer.wml  931) Skill Level: <i>Medium</i>
en/volunteer.wml  932) <br />
en/volunteer.wml  933) Likely Mentors: <i>Goodell</i>
en/volunteer.wml  934) <br />
en/volunteer.wml  935) Develop and implement a means of affording Blossom
en/volunteer.wml  936) users the ability to qualitatively describe the exit node that they
en/volunteer.wml  937) want.  The Internet is an inconsistent place: some Tor exit nodes see
en/volunteer.wml  938) the world differently than others.  As presently implemented, Blossom (a
en/volunteer.wml  939) tool for monitoring and selecting appropriate Tor circuits based upon
en/volunteer.wml  940) exit node requirements specified by the user) lacks a sufficiently rich
en/volunteer.wml  941) language to describe how the different vantage points are different.
en/volunteer.wml  942) For example, some exit nodes may have an upstream network that filters
en/volunteer.wml  943) certain kinds of traffic or certain websites.  Other exit nodes may
en/volunteer.wml  944) provide access to special content as a result of their location, perhaps
en/volunteer.wml  945) as a result of discrimination on the part of the content providers
en/volunteer.wml  946) themselves.  This project has two parts: (1) develop a language for
en/volunteer.wml  947) describing characteristics of networks in which exit nodes reside, and
en/volunteer.wml  948) (2) incorporate this language into Blossom so that users can select Tor
en/volunteer.wml  949) paths based upon the description.

en/volunteer.wml  950) Knowledge of Tor and Python are important; knowledge of
en/volunteer.wml  951) TCP, interprocess communication, and Perl will also be helpful.  An
en/volunteer.wml  952) interest in network neutrality is important as well, since the
en/volunteer.wml  953) principles of evaluating and understanding internet inconsistency are at
en/volunteer.wml  954) the core of the Blossom effort.

en/volunteer.wml  955) </li>
en/volunteer.wml  956) 

en/volunteer.wml  957) <li>
en/volunteer.wml  958) <b>Bring up new ideas!</b>
en/volunteer.wml  959) <br />
en/volunteer.wml  960) Don't like any of these? Look at the <a

en/volunteer.wml  961) href="<svnsandbox>doc/design-paper/roadmap-future.pdf">Tor development

en/volunteer.wml  962) roadmap</a> for more ideas.
en/volunteer.wml  963) </li>
en/volunteer.wml  964) 

en/volunteer.wml  965) </ol>
en/volunteer.wml  966) 

en/volunteer.wml  967) <h2><a class="anchor" href="#Coding">Coding and Design</a></h2>

volunteer.html    968) <ol>

en/volunteer.wml  969) <li>Tor relays don't work well on Windows XP. On

en/volunteer.wml  970) Windows, Tor uses the standard <tt>select()</tt> system

en/volunteer.wml  971) call, which uses space in the non-page pool. This means

en/volunteer.wml  972) that a medium sized Tor relay will empty the non-page pool, <a

en/volunteer.wml  973) href="https://wiki.torproject.org/noreply/TheOnionRouter/WindowsBufferProblems">causing

en/volunteer.wml  974) havoc and system crashes</a>. We should probably be using overlapped IO

en/volunteer.wml  975) instead. One solution would be to teach <a
en/volunteer.wml  976) href="http://www.monkey.org/~provos/libevent/">libevent</a> how to use
en/volunteer.wml  977) overlapped IO rather than select() on Windows, and then adapt Tor to

en/volunteer.wml  978) the new libevent interface. Christian King made a
en/volunteer.wml  979) <a href="https://tor-svn.freehaven.net/svn/libevent-urz/trunk/">good

en/volunteer.wml  980) start</a> on this in the summer of 2007.</li>

en/volunteer.wml  981) <li>We need to actually start building our <a href="<page
en/volunteer.wml  982) documentation>#DesignDoc">blocking-resistance design</a>. This involves

en/volunteer.wml  983) fleshing out the design, modifying many different pieces of Tor, adapting
en/volunteer.wml  984) <a href="http://vidalia-project.net/">Vidalia</a> so it supports the
en/volunteer.wml  985) new features, and planning for deployment.</li>

en/volunteer.wml  986) <li>We need a flexible simulator framework for studying end-to-end
en/volunteer.wml  987) traffic confirmation attacks. Many researchers have whipped up ad hoc
en/volunteer.wml  988) simulators to support their intuition either that the attacks work
en/volunteer.wml  989) really well or that some defense works great. Can we build a simulator
en/volunteer.wml  990) that's clearly documented and open enough that everybody knows it's
en/volunteer.wml  991) giving a reasonable answer? This will spur a lot of new research.
en/volunteer.wml  992) See the entry <a href="#Research">below</a> on confirmation attacks for
en/volunteer.wml  993) details on the research side of this task &mdash; who knows, when it's
en/volunteer.wml  994) done maybe you can help write a paper or three also.</li>

en/volunteer.wml  995) <li>Tor 0.1.1.x and later include support for hardware crypto accelerators

en/volunteer.wml  996) via OpenSSL. Nobody has ever tested it, though. Does somebody want to get

volunteer.html    997) a card and let us know how it goes?</li>

volunteer.html    998) <li>Perform a security analysis of Tor with <a
volunteer.html    999) href="http://en.wikipedia.org/wiki/Fuzz_testing">"fuzz"</a>. Determine

en/volunteer.wml 1000) if there are good fuzzing libraries out there for what we want. Win fame by

volunteer.html   1001) getting credit when we put out a new release because of you!</li>

volunteer.html   1002) <li>Tor uses TCP for transport and TLS for link
volunteer.html   1003) encryption. This is nice and simple, but it means all cells
volunteer.html   1004) on a link are delayed when a single packet gets dropped, and
volunteer.html   1005) it means we can only reasonably support TCP streams. We have a <a

en/volunteer.wml 1006) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#TransportIPnotTCP">list

en/volunteer.wml 1007) of reasons why we haven't shifted to UDP transport</a>, but it would
en/volunteer.wml 1008) be great to see that list get shorter. We also have a proposed <a

en/volunteer.wml 1009) href="<svnsandbox>doc/spec/proposals/100-tor-spec-udp.txt">specification
en/volunteer.wml 1010) for Tor and

en/volunteer.wml 1011) UDP</a> &mdash; please let us know what's wrong with it.</li>

volunteer.html   1012) <li>We're not that far from having IPv6 support for destination addresses
volunteer.html   1013) (at exit nodes). If you care strongly about IPv6, that's probably the
volunteer.html   1014) first place to start.</li>

volunteer.html   1015) </ol>
volunteer.html   1016) 

en/volunteer.wml 1017) <a id="Research"></a>
en/volunteer.wml 1018) <h2><a class="anchor" href="#Research">Research</a></h2>

volunteer.html   1019) <ol>

volunteer.html   1020) <li>The "website fingerprinting attack": make a list of a few
volunteer.html   1021) hundred popular websites, download their pages, and make a set of
volunteer.html   1022) "signatures" for each site. Then observe a Tor client's traffic. As
volunteer.html   1023) you watch him receive data, you quickly approach a guess about which
volunteer.html   1024) (if any) of those sites he is visiting. First, how effective is
volunteer.html   1025) this attack on the deployed Tor codebase? Then start exploring
volunteer.html   1026) defenses: for example, we could change Tor's cell size from 512
volunteer.html   1027) bytes to 1024 bytes, we could employ padding techniques like <a
volunteer.html   1028) href="http://freehaven.net/anonbib/#timing-fc2004">defensive dropping</a>,
volunteer.html   1029) or we could add traffic delays. How much of an impact do these have,
volunteer.html   1030) and how much usability impact (using some suitable metric) is there from
volunteer.html   1031) a successful defense in each case?</li>

volunteer.html   1032) <li>The "end-to-end traffic confirmation attack":
volunteer.html   1033) by watching traffic at Alice and at Bob, we can <a
volunteer.html   1034) href="http://freehaven.net/anonbib/#danezis:pet2004">compare
volunteer.html   1035) traffic signatures and become convinced that we're watching the same
volunteer.html   1036) stream</a>. So far Tor accepts this as a fact of life and assumes this
volunteer.html   1037) attack is trivial in all cases. First of all, is that actually true? How
volunteer.html   1038) much traffic of what sort of distribution is needed before the adversary
volunteer.html   1039) is confident he has won? Are there scenarios (e.g. not transmitting much)
volunteer.html   1040) that slow down the attack? Do some traffic padding or traffic shaping
volunteer.html   1041) schemes work better than others?</li>

en/volunteer.wml 1042) <li>A related question is: Does running a relay/bridge provide additional
en/volunteer.wml 1043) protection against these timing attacks? Can an external adversary that can't

en/volunteer.wml 1044) see inside TLS links still recognize individual streams reliably?

en/volunteer.wml 1045) Does the amount of traffic carried degrade this ability any? What if the
en/volunteer.wml 1046) client-relay deliberately delayed upstream relayed traffic to create a queue
en/volunteer.wml 1047) that could be used to mimic timings of client downstream traffic to make it
en/volunteer.wml 1048) look like it was also relayed? This same queue could also be used for masking
en/volunteer.wml 1049) timings in client upstream traffic with the techniques from <a
en/volunteer.wml 1050) href="http://www.freehaven.net/anonbib/#ShWa-Timing06">adaptive padding</a>,
en/volunteer.wml 1051) but without the need for additional traffic. Would such an interleaving of
en/volunteer.wml 1052) client upstream traffic obscure timings for external adversaries? Would the
en/volunteer.wml 1053) strategies need to be adjusted for asymmetric links? For example, on
en/volunteer.wml 1054) asymmetric links, is it actually possible to differentiate client traffic from
en/volunteer.wml 1055) natural bursts due to their asymmetric capacity? Or is it easier than
en/volunteer.wml 1056) symmetric links for some other reason?</li>

en/volunteer.wml 1057) <li>Repeat Murdoch and Danezis's <a
en/volunteer.wml 1058) href="http://www.cl.cam.ac.uk/~sjm217/projects/anon/#torta">attack from
en/volunteer.wml 1059) Oakland 05</a> on the current Tor network. See if you can learn why it
en/volunteer.wml 1060) works well on some nodes and not well on others. (My theory is that the
en/volunteer.wml 1061) fast nodes with spare capacity resist the attack better.) If that's true,
en/volunteer.wml 1062) then experiment with the RelayBandwidthRate and RelayBandwidthBurst
en/volunteer.wml 1063) options to run a relay that is used as a client while relaying the
en/volunteer.wml 1064) attacker's traffic: as we crank down the RelayBandwidthRate, does the
en/volunteer.wml 1065) attack get harder? What's the right ratio of RelayBandwidthRate to
en/volunteer.wml 1066) actually capacity? Or is it a ratio at all? While we're at it, does a
en/volunteer.wml 1067) much larger set of candidate relays increase the false positive rate
en/volunteer.wml 1068) or other complexity for the attack? (The Tor network is now almost two
en/volunteer.wml 1069) orders of magnitude larger than it was when they wrote their paper.) Be
en/volunteer.wml 1070) sure to read <a href="http://freehaven.net/anonbib/#clog-the-queue">Don't
en/volunteer.wml 1071) Clog the Queue</a> too.</li>

volunteer.html   1072) <li>The "routing zones attack": most of the literature thinks of
volunteer.html   1073) the network path between Alice and her entry node (and between the
volunteer.html   1074) exit node and Bob) as a single link on some graph. In practice,
volunteer.html   1075) though, the path traverses many autonomous systems (ASes), and <a
volunteer.html   1076) href="http://freehaven.net/anonbib/#feamster:wpes2004">it's not uncommon
volunteer.html   1077) that the same AS appears on both the entry path and the exit path</a>.
volunteer.html   1078) Unfortunately, to accurately predict whether a given Alice, entry,
volunteer.html   1079) exit, Bob quad will be dangerous, we need to download an entire Internet
volunteer.html   1080) routing zone and perform expensive operations on it. Are there practical
volunteer.html   1081) approximations, such as avoiding IP addresses in the same /8 network?</li>

en/volunteer.wml 1082) <li>Other research questions regarding geographic diversity consider
en/volunteer.wml 1083) the tradeoff between choosing an efficient circuit and choosing a random

en/volunteer.wml 1084) circuit. Look at Stephen Rollyson's <a

en/volunteer.wml 1085) href="http://swiki.cc.gatech.edu:8080/ugResearch/uploads/7/ImprovingTor.pdf">position
en/volunteer.wml 1086) paper</a> on how to discard particularly slow choices without hurting

en/volunteer.wml 1087) anonymity "too much". This line of reasoning needs more work and more
en/volunteer.wml 1088) thinking, but it looks very promising.</li>

en/volunteer.wml 1089) <li>Tor doesn't work very well when relays have asymmetric bandwidth

volunteer.html   1090) (e.g. cable or DSL). Because Tor has separate TCP connections between
volunteer.html   1091) each hop, if the incoming bytes are arriving just fine and the outgoing
volunteer.html   1092) bytes are all getting dropped on the floor, the TCP push-back mechanisms
volunteer.html   1093) don't really transmit this information back to the incoming streams.
volunteer.html   1094) Perhaps Tor should detect when it's dropping a lot of outgoing packets,
volunteer.html   1095) and rate-limit incoming streams to regulate this itself? I can imagine
volunteer.html   1096) a build-up and drop-off scheme where we pick a conservative rate-limit,
volunteer.html   1097) slowly increase it until we get lost packets, back off, repeat. We
volunteer.html   1098) need somebody who's good with networks to simulate this and help design
volunteer.html   1099) solutions; and/or we need to understand the extent of the performance
volunteer.html   1100) degradation, and use this as motivation to reconsider UDP transport.</li>
volunteer.html   1101) <li>A related topic is congestion control. Is our
volunteer.html   1102) current design sufficient once we have heavy use? Maybe
volunteer.html   1103) we should experiment with variable-sized windows rather
volunteer.html   1104) than fixed-size windows? That seemed to go well in an <a
volunteer.html   1105) href="http://www.psc.edu/networking/projects/hpn-ssh/theory.php">ssh
volunteer.html   1106) throughput experiment</a>. We'll need to measure and tweak, and maybe
volunteer.html   1107) overhaul if the results are good.</li>

volunteer.html   1108) <li>To let dissidents in remote countries use Tor without being blocked
volunteer.html   1109) at their country's firewall, we need a way to get tens of thousands of
volunteer.html   1110) relays, not just a few hundred. We can imagine a Tor client GUI that

en/volunteer.wml 1111) has a "Tor for Freedom" button at the top that opens a port and relays a

volunteer.html   1112) few KB/s of traffic into the Tor network. (A few KB/s shouldn't be too
volunteer.html   1113) much hassle, and there are few abuse issues since they're not being exit
volunteer.html   1114) nodes.) But how do we distribute a list of these volunteer clients to the
volunteer.html   1115) good dissidents in an automated way that doesn't let the country-level

en/volunteer.wml 1116) firewalls intercept and enumerate them? This probably needs to work on a

en/volunteer.wml 1117) human-trust level. See our <a href="<page documentation>#DesignDoc">early
en/volunteer.wml 1118) blocking-resistance design document</a> and our
en/volunteer.wml 1119) <a

en/volunteer.wml 1120) href="https://wiki.torproject.org/noreply/TheOnionRouter/TorFAQ#BlockingResistance">FAQ

en/volunteer.wml 1121) entry</a> on this, and then read the <a
en/volunteer.wml 1122) href="http://freehaven.net/anonbib/topic.html#Communications_20Censorship">censorship
en/volunteer.wml 1123) resistance section of anonbib</a>.</li>

en/volunteer.wml 1124) <li>Our censorship-resistance goals include preventing
en/volunteer.wml 1125) an attacker who's looking at Tor traffic on the wire from <a
en/volunteer.wml 1126) href="https://www.torproject.org/svn/trunk/doc/design-paper/blocking.html#sec:network-fingerprint">distinguishing
en/volunteer.wml 1127) it from normal SSL traffic</a>. Obviously we can't achieve perfect
en/volunteer.wml 1128) steganography and still remain usable, but for a first step we'd like to
en/volunteer.wml 1129) block any attacks that can win by observing only a few packets. One of
en/volunteer.wml 1130) the remaining attacks we haven't examined much is that Tor cells are 512
en/volunteer.wml 1131) bytes, so the traffic on the wire may well be a multiple of 512 bytes.
en/volunteer.wml 1132) How much does the batching and overhead in TLS records blur this on the
en/volunteer.wml 1133) wire? Do different buffer flushing strategies in Tor affect this? Could
en/volunteer.wml 1134) a bit of padding help a lot, or is this an attack we must accept?</li>

volunteer.html   1135) <li>Tor circuits are built one hop at a time, so in theory we have the
volunteer.html   1136) ability to make some streams exit from the second hop, some from the
volunteer.html   1137) third, and so on. This seems nice because it breaks up the set of exiting

en/volunteer.wml 1138) streams that a given relay can see. But if we want each stream to be safe,

volunteer.html   1139) the "shortest" path should be at least 3 hops long by our current logic, so
volunteer.html   1140) the rest will be even longer. We need to examine this performance / security
volunteer.html   1141) tradeoff.</li>

en/volunteer.wml 1142) <li>It's not that hard to DoS Tor relays or directory authorities. Are client

volunteer.html   1143) puzzles the right answer? What other practical approaches are there? Bonus
volunteer.html   1144) if they're backward-compatible with the current Tor protocol.</li>

en/volunteer.wml 1145) <li>Programs like <a
en/volunteer.wml 1146) href="https://torbutton.torproject.org/dev/">Torbutton</a> aim to hide
en/volunteer.wml 1147) your browser's UserAgent string by replacing it with a uniform answer for
en/volunteer.wml 1148) every Tor user. That way the attacker can't splinter Tor's anonymity set
en/volunteer.wml 1149) by looking at that header. It tries to pick a string that is commonly used
en/volunteer.wml 1150) by non-Tor users too, so it doesn't stand out. Question one: how badly
en/volunteer.wml 1151) do we hurt ourselves by periodically updating the version of Firefox
en/volunteer.wml 1152) that Torbutton claims to be? If we update it too often, we splinter the
en/volunteer.wml 1153) anonymity sets ourselves. If we don't update it often enough, then all the
en/volunteer.wml 1154) Tor users stand out because they claim to be running a quite old version
en/volunteer.wml 1155) of Firefox. The answer here probably depends on the Firefox versions seen
en/volunteer.wml 1156) in the wild. Question two: periodically people ask us to cycle through N
en/volunteer.wml 1157) UserAgent strings rather than stick with one. Does this approach help,
en/volunteer.wml 1158) hurt, or not matter? Consider: cookies and recognizing Torbutton users
en/volunteer.wml 1159) by their rotating UserAgents; malicious websites who only attack certain
en/volunteer.wml 1160) browsers; and whether the answers to question one impact this answer.
en/volunteer.wml 1161) </li>

volunteer.html   1162) </ol>
volunteer.html   1163) 

en/volunteer.wml 1164) <p>

en/volunteer.wml 1165) <a href="<page contact>">Let us know</a> if you've made progress on any
en/volunteer.wml 1166) of these!

en/volunteer.wml 1167) </p>

volunteer.html   1168) 

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volunteer.html   1170) 

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